1. [3 interchangeable grinding heads] ： 3 grinding heads are made of high quality quartz micro-mineral crystals and are of different thicknesses (coarse grinding head for stubborn calluses, medium grinding head for rough, dead skin, fine grinding head for daily skin care). You can choose the appropriate replacement head according to the hardness of your cornea. 2. [2 speeds with one button] ： The electronic callus rasp has a powerful motor with high torque. You can easily switch it to 2 speeds: 1900 RPM and 2200 RPM.Low speed is suitable for mild dead skin or sensitive skin care. High speed is suitable for stubborn thick callus or deep cleansing. Professional equipment will help keep your heels and feet soft, smooth, and healthy. 3. [Vacuum suction & heat dissipation] ： Unlike the conventional roller-style, our new callus remover is equipped with a rotating planetary gear, can grind calluses more effectively in larger areas. A specially designed vacuum function can suck in tiny skin calluses and keep them from flying around. The holes in the sanding heads also help dissipate heat and ensure that the devices are not burned out by the heat generated during work. 4. [USB charging & LCD screen] ： With a large battery capacity of 1200 mAh, the USB charging time is 2 to 2.5 hours and can work for you about 100 to 150 minutes continuously. The LCD display on the housing of the corneal rasp allows you to see exactly the remaining battery level. Thanks to the wireless design, you can also use the electric callus remover on the go. 5. [IPX7 Waterproof & Easy to Clean] ： High water resistance, you can enjoy a comfortable massage even in the bathroom. All parts of the foot care device can be rinsed under running water. The attached removal tool and cleaning brush will help you disassemble the grinding heads easily and remove the debris that has been collected, ensuring you have a hygienic and comfortable experience.